Do you know the overload protection of the adapter?

What is adapter overload protection? How should it be done? During the development process of new switching power adapter products, in order to ensure that the adapter can adapt to the operating requirements of different environments during use and provide users with continuous and stable current-to-voltage conversion work, engineers Adapters are usually provided with appropriate output overload protection to ensure safe operation of the adapter.

Introducing two currently widely used output overload protection technologies:

1. Constant power limit protection method

The constant input power limiting protection method is one of the more common switching power adapter output protection technologies at present. The protection principle of this method is to protect the primary circuit by limiting the maximum transmission power. But in a flyback converter, this technique can hardly protect the secondary output components. For example, in a discontinuous flyback converter, the peak current on the primary side is already limited, that is, a limited transmitted power is given. When the load resistance decreases and the load exceeds its limit, the output voltage begins to decrease. Precisely because the product of the voltage and current of the specified input and corresponding output, when the output voltage starts to decrease, the output current will increase. During a short circuit, the secondary current will become very large, consuming all the power in the switching power supply. This form of power limitation is generally only used as a supplementary form of certain limitations, such as secondary side current limiting in circuits with supplementary limitations.

2. Flyback overpower limiting protection method

The counterattack overpower protection method is currently widely used in domestic adapter R&D and manufacturer production processes. This protection technology is an extension of the high-speed form. In this form, there is a circuit to monitor the primary current and secondary voltage. , reducing power when the output voltage decreases. Through this method, the output current is reduced when the load resistance decreases, preventing the secondary components from being damaged by excessive stress. The disadvantage is that locking will occur when used with non-linear loads. The above is the overload protection of the adapter, I hope it can help you.